1. Technical Field
The present invention relates to an on-vehicle electronic control device such as an engine control device configured such that electrically divided first and second control circuit units serially exchange monitor and control signals with each other, and more particularly to the improvement of an on-vehicle electronic control device for efficiently and accurately transmitting digitally converted analog signals.
2. Related Art
An on-vehicle control device is publicly known which is configured such that electrically divided first and second control circuit units serially exchange monitor and control signals by a periodic transmission packet that is a downlink communication, a periodic report packet that is an uplink communication, and a report reply packet that is an uplink communication corresponding to a read request packet that is a downlink communication.
For example, Japanese Patent Application Publication (JP-A) No. 2003-285702 (see paragraph nos. 0020 to 0114 and FIG. 2) discloses an on-vehicle electronic control device comprising: a microprocessor to which a parent station serial/parallel converter is connected to configure a first control circuit unit; and a communication control circuit unit to which a child station serial/parallel converter serially connected to the parent station serial/parallel converter is connected to configure a second control circuit unit, wherein the communication control circuit unit includes first storing means that stores data transmitted from the parent station to the child station, distribution storing means which, when command data stored in the first storing means is a write/set command, transfers the command data to a device memory, reply packet generating means that generates uplink reply information with respect to the microprocessor, second storing means that sequentially stores the reply information and reads the reply information on a first-in first-out basis while waiting out congestion, and reply packet organizing means that adds and sends back latest information.
The reply packet is a packet with which the on-vehicle electronic control device can periodically send back ON/OFF information of 16 points or less and periodically send back digital conversion values of analog signals of 15 points or less.
Furthermore, JP-A No. 8-23276 (see paragraph nos. 0012 to 0026 and FIG. 1) discloses an analog/digital conversion device comprising: (1) a multiplexer unit that selects, in accordance with a selection command, one channel from among plural channels to which analog signals are inputted; (2) an analog/digital conversion unit that converts, to a digital signal, the one analog signal selected by the multiplexer unit; and (3) a control unit that outputs the selection command to the multiplexer unit and reads the digital signal converted by the analog/digital conversion unit, wherein (4) the multiplexer unit includes a channel return unit which, when the analog/digital conversion unit completes conversion, returns the selected channel to the control unit, and (5) the control unit includes an abnormality judging unit that judges as abnormal when the channel outputted to the multiplexer unit and the channel returned from the channel return unit do not match.
JP-A No. 8-23276 also discloses an analog/digital conversion device comprising: (6) a multiplexer unit that selects, in accordance with a selection command, one channel from among plural channels to which analog signals are inputted; (7) an analog/digital conversion unit that converts, to a digital signal, the one analog signal selected by the multiplexer unit; and (8) a control unit that outputs the selection command to the multiplexer unit and reads the digital signal converted by the analog/digital conversion unit, wherein (9) the control unit includes an abnormality judging unit that measures the amount of time required for the analog/digital conversion unit to complete conversion after the control unit has outputted a conversion start command to the analog/digital conversion unit and judges as abnormal when the amount of time required for conversion is equal to or greater than a predetermined longest time.
Moreover, JP-A No. 2002-209886 (see paragraph nos. 0009 to 0024 and FIG. 1) discloses an ultrasound diagnostic device including: (1) an ultrasound probe including a piezoelectric vibrator that receives an ultrasound echo corresponding to an ultrasound pulse transmitted inside a test subject and generates a received echo signal; (2) A/D converting means that converts the received echo signal to parallel data at a timing matching a sampling period; (3) time division outputting means that divides into plural bit strings the parallel data outputted at the same time from the A/D converting means and time-divisionally switches and outputs each bit string in a period shorter than the sampling period; (4) and signal processing means that restores the original parallel data on the basis of the bit strings outputted by the time division outputting means, wherein the time division outputting means includes (5) a latch circuit that temporarily retains and outputs the parallel data at a timing matching the sampling period and (6) a selector circuit that plurally divides and retrieves the bit strings outputted by the latch circuit and switches and outputs each bit string in a period shorter than the sampling period.
The on-vehicle electronic control device of JP-A No. 2003-285702 is configured such that it can alternately periodically report ON/OFF information that is switch signal input and digital information that is the digital conversion value of the analog input signal, but there is no reference to abnormality judging and abnormality processing of the analog conversion data.
Further, the analog/digital conversion device of JP-A No. 8-23276 has the drawback that, when attempting to obtain digital information of analog signals, it becomes necessary to transmit before hand a channel designation command each time, so the burden of communication control becomes excessive when attempting to obtain a lot of digital information frequently.
Moreover, the analog/digital conversion device of JP-A No. 8-23276 also has the drawback that abnormality judgment is slow and needless transmission must be performed because it is configured to perform abnormality judgment of the A/D converter after it has transmitted A/D-converted digital information.
Moreover, the ultrasound diagnostic device of JP-A No. 2002-209886 is configured to divide A/D conversion data into a high-order bit group and a low-order bit group, transmit the groups, and combine the groups at the reception side, but when the timing of data division is asynchronous with the A/D conversion timing, there is the risk that data division abnormality will occur, so that when the groups are combined at the reception side, the high-order bit group of old data and the low-order bit group of new data become combined as one data group, for example.